Point-to-Point Also called app-to-app, this approach involves hand-coding integration, and typically takes place within an enterprise. This remains a tried-and-true method for moving data from point A to point B. Most companies have some point-to-point, and many?almost 50 percent according to a 2001 survey by AMR Research in Boston?continue to hardwire applications.

This approach has problems. Think of a company running 100 applications, each in its own box; then picture how many lines need to be drawn to connect those boxes, given that a bunch of those apps would connect to more than one app?it’s one big brain cramp. When one app needs to be changed, every connection to that app must change. And development and maintenance costs can be high.

Middleware Whether it’s called object management, event management, session management, data translation or one of many acronyms, middleware creates a layer between applications. The applications are not connected point-to-point; they’re connected to a middle layer, which receives the data, translates it, then sends it on its merry way. Many companies use message-oriented middleware such as IBM’s MQ series and Microsoft’s MSMQ for one-way exchanges of data.

EAI products, also called integration servers, describe more powerful kinds of middleware. Major players include BEA, IBM, SeeBeyond, Tibco, Vitria and WebMethods, although many companies have built their own proprietary EAI systems.

EAI tools are designed to integrate the information in companies’ back-office systems with their front-office applications using a single integration layer. These products come packaged with connectors (also called adapters) that can, for example, connect ERP systems to mainframes and CRM systems. Many companies rely on these adapters?at $100,000 a pop?to integrate heterogeneous systems.

Business Process Management (BPM) BPM is a relatively new buzzword, touted as the next generation enterprise integration software. AMR Research defines BPM as "software that integrates data, applications and people together through a common business process." It aims to bring the business and IS side together to figure out cross-functional business processes, which include suppliers, customers, employees and partners, then streamline and automate them.

Web Services Take your pick: Web services is either poised to take off or will make only minor ripples. Its standards-based technology will let disparate systems talk to each other over the Internet or Internet protocol-based networks, regardless of platform or language. Most of the executives in this story are experimenting with Web services. Amazon.com CIO Richard L. Dalzell says the online retailer uses it as one of the interfaces for its more than 600,000 Associates Program websites that connect back to Amazon.com. And vendors such as Microsoft and SAP are beginning to support Web services in their products. But despite the hype, Web services is in its infancy, and widespread adoption won’t happen overnight.